The present invention relates to a molded article comprising a rigid support having a plurality of perforations, and a molded flexible hollow member of thermoplastic material. Portions of the flexible hollow member extend through at least some of the perforations of the rigid support, and the edges of the perforations are embedded in the flexible material extending there through. The flexible material extending through the perforations serves to fixedly attach the flexible member to the rigid support. The present invention also relates to a process of preparing the molded article.
Flexible hollow thermoplastic articles, e.g., cushions, can be prepared by means of thermoplastic blow molding processes. Blow molding typically involves a multi-stage process. In the first stage, a flexible thermoplastic feed material, e.g., in the form of pellets, is extruded, typically in an extruder, and the resulting molten extrudate is passed through a die to form a hollow molten tube, which is referred to as a parison. The parison is drawn through or into an open mold. The mold is closed around the parison, pinching off at least one end of the parison. Compressed gas is then fed into the interior of the parison, which expands to fill the interior of the closed mold. While maintaining the internal pressure within the parison, the expanded parison is allowed to cool and solidify within the mold. The pressure within the solidified parison is released, the mold is opened, and a flexible hollow blow molded article is removed. Flexible hollow thermoplastic articles may also be prepared by other art recognized processes, which include, for example, twin-sheet thermoforming, rotational molding, thermoplastic welding (e.g., vibration and/or radio frequency welding), two-piece over-molding and lost-core molding.
The flexible hollow thermoplastic member or bladder, prepared for example by blow molding, is typically attached to a support structure. In the case of seat cushions, the flexible hollow thermoplastic bladder is attached to a seat back support and/or seat bottom support by means of, for example, a fabric jacket. The fabric jacket is attached to the support structure, e.g., by means of rivets and/or loops, and covers and tightly holds the flexible hollow thermoplastic bladder against the support structure. The flexible bladder may also be further or alternatively attached to the support structure by means of, for example, adhesives. The flexible bladder or cushion may be filled with air, or another material, such as a polymeric foam, e.g., a polyurethane foam.
Such methods of attaching flexible hollow thermoplastic bladders or cushions to a support structure, as described above, typically involve a series of manufacturing steps, and the use of additional materials, e.g., fabric jackets, rivets and adhesives. In addition, the position of the flexible hollow thermoplastic bladder or cushion can undesirably shift relative to or pull away from the support structure.
A need accordingly exists to develop molded articles, e.g., cushioned seats, in which the molded flexible hollow thermoplastic member, such as a bladder or cushion, is more securely fixed or attached to the rigid support of the article. A need also exists with regard to the development of new methods of preparing such molded articles in which the flexible member is concurrently molded and fixedly attached to the support structure, thereby reducing the number of manufacturing steps required.
U.S. Pat. No. 6,120,100 discloses a head rest assembly that is fabricated by a blow molding process, and which includes a skin surrounding a foam cushion, and an insert secured to the skin. The skin includes a channel dimensioned to receive the peripheral edge of the insert therein. The insert may be adhered to the skin either before or during the blow molding process.
In accordance with the present invention, there is provided a molded article comprising:
(a) a rigid support having a surface and a plurality of perforations having edges; and
(b) a molded flexible member of thermoplastic material, at least a portion of said flexible member being in abutting relationship with at least a portion of the surface of said support, said flexible member having a hollow interior,
wherein a portion of said flexible member extends through at least some of the perforations of said rigid support, the edges of said perforations being embedded in the portions of the flexible member extending therethrough, thereby fixedly attaching said flexible member to said rigid support.
In further accordance with the present invention, there is also provided a method of preparing a molded article comprising a molded flexible hollow thermoplastic member fixedly attached to a rigid support, said method comprising:
(a) placing said rigid support in a mold, said rigid support having a plurality of perforations having edges, a first surface and a second surface; and
(b) blow molding a thermoplastic parison precursor of said flexible member against the first surface of said rigid support;
wherein a portion of the thermoplastic material of said thermoplastic parison extends through at least some of said perforations of said rigid support, the edges of said perforations being embedded in the plastic material extending therethrough, thereby attaching fixedly said flexible member to said rigid support.
The features that characterize the present invention are pointed out with particularity in the claims, which are annexed to and form a part of this disclosure. These and other features of the invention, its operating advantages and the specific objects obtained by its use will be more fully understood from the following detailed description and accompanying drawings in which preferred embodiments of the invention are illustrated and described.
Unless otherwise indicated, all numbers or expressions, such as those expressing structural dimensions, quantities of ingredients, etc. used in the specification and claims are understood as modified in all instances by the term xe2x80x9cabout.xe2x80x9d